mbstowcs, mbsrtowcs - Convert a multibyte character string
to a wide-character string
#include <stdlib.h>
size_t mbstowcs(
wchar_t *pwcs,
const char *s,
size_t n ); #include <wchar.h>
size_t mbsrtowcs(
wchar_t *pwcs,
const char **s,
size_t n,
mbstate_t *ps );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
mbstowcs(), mbsrtowcs(): XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Points to the array where the result of the conversion is
stored. Points or indirectly points to the multibytecharacter
string to be converted. Specifies the number of
wide characters in the destination array. Points to an
mbstate_t structure containing the conversion state of the
multibyte character in s (for mbrtowc() only).
The mbstowcs() function converts a multibyte-character
string into a wide-character string, which is stored at a
specified location. The function does not examine or convert
any characters that follow a null byte, which is converted
and stored as a wide-character code with value
zero. The function does not store more than n wide characters
in pwcs. When operating on overlapping strings, the
behavior of this function is undefined.
Behavior of the mbstowcs() function is affected by the
LC_CTYPE category of the current locale. In locales that
use shift-state encoding, the array pointed to by the s
parameter begins in the initial shift state.
The mbsrtowcs() function is a restartable version of
mbstowcs(). Restartable conversion functions obtain and
store the conversion state in an mbstate_t structure that
can be read and changed by subsequent calls to the same or
other restartable conversion functions.
[Tru64 UNIX] The mbsrtowcs() and other restartable versions
of conversion functions are functional only when
used with locales that support shift-state encoding. Currently,
the operating system does not provide any locales
that support shift-state encoding, so the mbstowcs() and
mbsrtowcs() functions do not differ in terms of run-time
behavior.
When the mbstowcs() and mbsrtowcs() functions encounter an
invalid multibyte character during conversion, they return
a value of -1 cast to size_t and set errno to indicate the
error. Otherwise: The mbstowcs() function returns the number
of characters stored in the output array (or required
if pwcs is null), not including a terminating null wide
character, if any. When the return value is n, the output
array is not null-terminated. The mbsrtowcs() function
returns the number of characters stored in the output
array, not including a terminating null wide character, if
any.
If the following condition occurs, the mbstowcs() and
mbsrtowcs() functions set errno to the corresponding
value: The s parameter contains an invalid multibyte character.
Functions: btowc(3), mblen(3), mbsinit(3), mbtowc(3),
wcstombs(3), wcslen(3), wctob(3), wctomb(3)
mbstowcs(3)
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